Hmmm.
I just happen to have a map, with, remarkably, all these sites on. Just send me all your money, and the map's yours. 'Buried Treasure', at Kenley or elsewhere is the aviation preservation's version of the nice man from Africa who just needs to use your bank account for a while...
I can actually think of only one aircraft recovered from underground to fly - the ex-Col Pay P-40 which was used as a dam landfill in Canada. There are surely more recovered - anyone? Aviation Archaeology, while a valid pursuit in itself mainly results in lumps of twisted metal. Eligible would be an aircraft that is now preserved, complete, and recognisable for what it was. (Sand, jungle, water and ice have all yielded 'complete' aircraft - don't tell us about those.)
But the stories of secret caches out number recoveries the usual 100 - 1.
Cheers